Antithrombin - functional activity - plasma

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Eurofins Biomnis code

AT

Synonyms
  • Antithrombin - activity
  • AT
Specialty

Haematology

Clinical significance

Antithrombin is a glycoprotein which is synthesized in the liver and which acts as a physiological inhibitor of thrombin and, to a lesser extent, of certain coagulation factors (including Xa, IXa, XIa and XIIa). Its activity is hugely potentiated by heparin. Hereditary deficiency (an autosomal dominant trait) is fairly rare but results in widespread venous thrombosis leading to pulmonary embolism. Acquired deficiency can occur in conditions in which there is nephrosis or disseminated, intravascular coagulation. It is also possible in patients with impaired liver function and it can be drug-induced (by oral contraceptives and L-asparaginase). This test cannot be performed if heparin has been administered within the last 10 days, if there is any evidence of recent thrombosis, or in pregnant women. This functional assay is possible in patients being treated with vitamin K antagonists (e.g. warfarin).

Preanalytics
  • A tube specifically for this analysis : No
Further information

Always specific the treatment and clinical context of the test prescription: Unfractionated heparin may induce a weak decrease in antithrombin level.
The interference is reduced with HMWH.
In case the patient is under treatment, the test can be performed. Deficiency will be rulled out if antithrombin level is normal. If the result is lowered, a repeat testing will have to be performed at distance from any treatment. Do not collect samples from a patient under direct oral anticoagulants.
Do not measure the activity of antithrombin if treatment in progress with direct anticoagulant active by oral of type anti-Xa (XARELTO, ELIQUIS).
It is advisable to send us a frozen and centrifuged citrate sample in compliance with the GFHT pre-analytical recommendations.
The assay should be performed after a 5-day discontinuation of the ODA treatment

Documents to download
Methodology

Chromogenic method

Turnaround time

1 day

Testing Laboratory

Contact(s)
Customer Care